In theory, more development = more property taxes. But reading the OP's post, it sounded like the developer was avoiding those taxes.
It's fairly common for big developers to get temporary tax abatements for developing big projects. I have seen "temporary" over 10 years, and I wouldn't be surprised to learn that sometimes it goes beyond 20.
The OP mentioned Seattle, which apparently has a boilerplate 12-year tax abatement for multi-family developments: https://clarknuber.com/seattles-multifamily-property-tax-exe...
12 years is a long time to underfund municipal services in an area.